Navy Asbestos Medical Surveillance Program 1990-1999: demographic features and trends in abnormal radiographic...

A 10-year cross-sectional analysis was conducted for 233,353 radiographic examinations performed as part of the Navy Asbestos Medical Surveillance Program. Demographic and temporal trends in abnormal radiographs were assessed during this analysis. Abnormal radiograph prevalence increased significantly with age, and abnormal radiographs were nearly 30 times more likely to occur among participants 60 to 69 years of age, compared with participants < 20 years of age (odds ratio, 27.57; 95% confidence interval, 14.75-51.53). Men were 5 times more likely than women to have an abnormal radiograph (odds ratio, 5.84; 95% confidence interval, 5.02-6.80); after controlling for differences in age, this gender association remained significant only for participants > 30 years of age. The proportion of abnormal radiographs decreased significantly over the study period [chi2 (df = 1) test for trend, chi2 = 198.7, p < 0.0001], although the cohort mean age increased. Despite aging of the Asbestos Medical Surveillance Program population, the overall prevalence of radiographic abnormalities is declining; future studies should examine the reasons for this observation.